1. Field of the Invention (Technical Field)
The present invention relates to the field of fluid monitoring and treatment apparatuses.
2. Background Art
Many different instruments are required to measure the parameters of wastewater, process water, and other fluids that are sampled. Maintaining these individual components and tracking the data from these individual components is cumbersome. For example, samplers, flow meters, pH meters, temperature gauges, conductivity and ORP meters, etc., are all used to monitor and track the quality of wastewater, process water, or other fluid being sampled. In fact, most water treatment monitoring systems today comprise an assortment of individual meters and gauges. These individual components are not integrated.
Currently, microprocessor-based control systems are being used in modern industrial processes, including water treatment applications and programmable logic controllers (PLCs) are microprocessor-based. Programmable logic controllers were designed to be a microprocessor-based replacement for hardwired relay logic historically used in industrial control systems. PLCs are programmed to simulate the same type of control that could be accomplished by sets of relays and timers. This is referred to as logic control. Logic control allows certain specific actions to occur based upon other actions or conditions. PLCs have the ability to quickly scan inputs and control outputs based upon the condition of the inputs. However, most PLCs do not have any provisions for storing data (referred to as data logging) or for displaying data on a screen without an additional operator interface.
PLCs also do not have the ability to obtain data directly from water treatment sensors such as pH, ORP, conductivity, etc. This means that an additional meter or transmitter has to be installed between the PLC and the appropriate sensor. A discrete signal is often sent from a relay output on a meter to a discrete input on the PLC. Alternatively, an analog signal may be sent from the meter to an analog input on the PLC. Use of meters in addition to the PLC means additional expense, additional wiring, and additional programming since the meter will have to be programmed for alarm set points and alarm deadband. In summary, current PLCs are used primarily for control. They tend to be difficult if not impossible to use for calculating, manipulating, displaying or storing data. They cannot be used to obtain input directly from most water treatment sensors.
In conventional monitoring systems, it is common to have a number of separate meters monitoring the analytical parameters listed above. Each of these meters may then produce an analog output, which is recorded by some type of control device, such as a PLC. Many PLCs are designed having interchangeable input/output modules. These modules plug into a xe2x80x9crackxe2x80x9d or a piece of hardware with multiple connections to some type of data bus, much like the ISA slots in a personal computer. However, in the case of analytical parameters such as pH, oxidation reduction potential (ORP), conductivity, dissolved oxygen, turbidity, corrosion rate, specific ion, etc., conventional systems monitor these parameters with separate discrete instruments. These instruments then send a signal, usually some type of analog signal, to a standard input module on the PLC. Presently available systems do not have input/output modules for analytical parameters available for standard PLCs.
With a conventional PLC, the monitoring and control system is configured by selecting the assorted meters necessary to monitor the parameters of interest. These are hardwired to the PLC and both the PLC and the meters have to be programmed. In the case of the present invention, configuration is done via software rather than hardwiring, and input/output modules are used to monitor and control analytical parameters as well as other parameters. The present invention also allows the operator to log data as well as display data.
Patents which disclose devices designed to combine the different conductivity meters, pH meters, ORP meters, flow meters, etc. but unlike the present invention include U.S. Pat. No. 5,091,863, to Hungerford, et al., entitled Automatic Fluid Sampling and Flow Measuring Apparatus and Method, which discloses a device to monitor sewer flows and which is to be mounted inside a manhole. U.S. Pat. No. 5,172,332, to Hungerford, et al., entitled Automatic Fluid Sampling and Monitoring Apparatus and Method, is essentially the same device as that in U.S. Pat. No. 5,091,863 but includes broader program storage memory and data storage memory. U.S. Pat. No. 5,299,141, to Hungerford, et al., entitled Automatic Fluid Monitoring and Sampling Apparatus and Method, again discloses the same device as in the prior two patents but includes a photoelectric type sensor. U.S. Pat. No. 5,633,809, to Wissenbach, et al., entitled Multi-Function Flow Monitoring Apparatus with Area Velocity Sensor Capability, again discloses a similar device to the prior three patents but includes input/output points. However, these are fixed. Additional analog inputs and discrete outputs cannot be added. All of these devices are to be used in monitoring sewer pipes and are mounted in manholes, and their primary purpose is for flow measurement.
Unlike the aforementioned devices, the present invention is reprogrammable even after the unit has been installed. The present invention is designed to be programmed for each application, including logic control functions. It can be used for any type of fluid monitoring and control, not just wastewater. The aforementioned parameters can all be monitored directly from the sensor with the various input/output cards without any additional instrumentation. The input/output cards are interchangeable and selectable by the operator and can be interfaced directly to the data bus from the various instruments. The applications for this type of input/output card configuration are endless. Analytical process parameters have not been directly monitored by devices in the prior art. Because it is compact and flexible, the present invention can be mounted on a control panel with standard bracketing. This unique apparatus can be used to monitor streams in industrial settings as well as in the field.
Reverse osmosis (RO) is a simple process wherein water is forced through a membrane under pressure. The membrane rejects both dissolved and suspended solids thus producing a very pure permeate. The process may be described as filtration on a molecular or ionic level. Unlike most filtration processes, however, RO is not simple to monitor. In order to determine whether an RO unit is operating properly, a number of parameters must be recorded such as those listed in Table 1. FIG. 24 is a diagram demonstrating typical RO monitoring points in an RO system. Feed water enters through inlet 500 and is fed through RO membranes within an array of vessels shown generally at 508 and 510. Feed pressure is measured at header 504 and reject pressure at 506. Water exits through outlet 502.
After recording the raw data listed above, yet another set of calculated values must be prepared using the raw data collected from the RO, as shown in Table 2. It is only from these calculated values that a determination can be made regarding the performance of the RO unit.
The following is a closer examination of how each of these parameters is calculated and used to monitor RO performance.
As the feed water passes through the pressure vessels of an RO unit, it encounters resistance due to the feed spacers in the membrane elements. Therefore, even new elements present some resistance to flow as the water passes through the system. As the membrane elements experience use, foulants build up on the surface of the membrane and in the feed spacer material itself. As these foulants accumulate, the resistance to flow of the feed water increases. This resistance to flow may be measured as a differential pressure across the vessel.
Differential pressures are calculated using the following equation:
DP=Pfxe2x88x92Pr
Where:
DP=Differential Pressure
Pf=Feed Pressure (Vessel Inlet)
Pr=Reject Pressure (Vessel Outlet)
In most RO systems there is more than one vessel in the array. Since the vessels are all piped into a single header on both the inlet and outlet, these pressures are monitored on the header resulting in one feed pressure and one reject pressure per array.
Many RO systems also have more than one array or stage. In this case, pressure must be monitored at three or more locations and the differential pressures are calculated as follows:
DP1=Pfxe2x88x92Pi
DP2=Pixe2x88x92Pr
Where:
DP1=Differential Pressure Across the First Stage
DP2=Differential Pressure Across the Second Stage
Pf=Feed Pressure (Vessel Inlet)
Pi=Interstage Pressure (Between Vessels)
Pr=Reject Pressure (Vessel Outlet)
As in the case of most RO parameters, it is important to monitor the change in differential pressure over time. As foulants build up on the membrane surface and in the channels of the feed spacer, the differential pressure will increase. It is important to act promptly if the differential pressure begins to increase. If the differential pressure is allowed to increase excessively, structural damage to the membrane elements is likely to occur. It is also more difficult to clean the membrane elements if they have acquired a high differential pressure since differential pressure restricts flow. The cleaning solution will have to flow through the same restricted feed channels as the feed water.
In multi-stage systems it is advantageous to observe the change in differential pressure relative to the stage. If the first stage shows a high differential pressure relative to the second stage, it may mean that the fouling is due to suspended solids being caught in the front end of the flow path. If the second stage shows a high differential pressure relative to the first stage, it may be an indication of scaling taking place in the second stage.
Recovery refers to the amount of permeate being produced by the RO relative to the amount of feed water. It is calculated with the following equation:
%R=(Fp/Ff)xc3x97100%
Where:
%R=Percent Recovery
Fp=Permeate Flow
Ff=Feed Flow
The following example demonstrates the importance of recovery. If an RO unit is operating at 75% recovery, 25% of the original feed water volume is being rejected. This means that most, if not all, of the foulants in the feed water are now contained in only 25% of the volume that contained them when they entered the RO. In other words, they have been concentrated four times. Suppose the recovery is increased to 80%. While this may seem like a rather insignificant increase of only 5%, now only 20% of the original feed water volume is being rejected. The foulants that were in the feed water have now been concentrated five times. If the recovery had been increased to 90%, the foulants would have been concentrated ten times. Recoveries should be monitored closely. Even brief periods of high recovery can have detrimental effects on the cleanliness of the membrane.
While concentration can be read directly via conductivity meters, it can also be calculated. Conductivity is a physical characteristic; i.e. the ability of the water to conduct an electric current. Concentration is a chemical characteristic referring to the amount of solids chemically dissolved in the water. If the solids dissolved in the water are ionic, concentration can be correlated to conductivity. This is due to the fact that the dissolved ions are the means by which the current (electrons) flows through the water. Fortunately, in most naturally occurring waters, the vast majority of the dissolved solids are in the form of ions. On the downside, the exact correlation between conductivity and concentration depends upon the type of ions present.
For example, if the water contains monovalent ions such as sodium, chloride, hydrogen, hydroxide, etc., the concentration (in mg/l) will be approximately one half of the conductivity (in micro Siemens). This relationship is often referred to as a conversion factor and is used as follows:
Concentration (in mg/l)=Conductivity (in uS)xc3x97Conversion Factor
In waters containing predominantly multivalent ions such as calcium, magnesium, sulfate, carbonate, etc., the conversion factor may be as high as 0.85. Since most waters contain a mixture of monovalent and multivalent ions, a common conversion factor is 0.67. Most conductivity meters which give results in mg/l (concentration) simply multiply the conductivity by this 0.67 conversion factor.
Salt rejection refers to the ability of the membrane to reject the dissolved solids (salts) in the feed water. There are a number of ways to calculate salt rejection. One of the most popular is the feed-reject average method. This is calculated as follows:
%SR=100xe2x88x92((Cp/((Cf+Cr)/2))xc3x97100%)
Where:
%SR=Percent Salt Rejection
CP=Concentration of Dissolved Solids in Permeate
Cf=Concentration of Dissolved Solids in Feed Water
Cr=Concentration of Dissolved Solids in Reject
Salt rejection is important since it describes the quality of the water being produced by the RO unit. Even more important, a change in salt rejection may mean a change in membrane condition. It can indicate fouling, scaling, or chemical attack. It may also indicate a mechanical failure such as a leaking O-ring. Sudden changes in salt rejection are most often due to mechanical problems. Gradual changes are usually due to changes in membrane condition. For this reason, salt rejection must be monitored closely.
Many RO operators mistakenly use actual permeate flow to indicate RO performance. While this may be effective in some cases, it is usually not a good way to monitor RO performance. Actual permeate flow from a given RO unit is a function of three different variables: net drive pressure, water temperature, and membrane condition. Membrane condition, is the single variable that describes RO performance. A change in membrane condition would indicate such things as fouling, scaling, and chemical attack.
If the first two variables were to stay constant, a decline in actual permeate flow would indicate a change in membrane condition. Unfortunately, this is seldom the case. The other variables can change. When they do, a change in actual permeate flow may no longer mean a change in RO performance. Even worse, RO performance may be changing (i.e., membrane fouling or damage may be occurring) although no change in actual permeate flow is seen.
Calculating normalized permeate flow simply means that any changes that occur in the first two variables must be taken into consideration. If changes in net drive pressure and water temperature are accounted for by calculating normalized permeate flow and a change in permeate flow still occurs, then this change has to be due to the third variable, membrane condition. In other words, a change in membrane condition is taking place, which usually means the membrane must be cleaned.
The following is a closer examination of the first two variables which affect permeate flow, net drive pressure and water temperature.
Net Drive Pressure (NDP) refers to the summation of four different pressures acting upon the RO membrane during operation of an RO unit. FIG. 25 shows the forces acting upon an RO membrane. Two of these pressures are positive and two are negative. Applied pressure is the largest of the two positive pressures making up NDP. Applied pressure is created by the high pressure pump supplying feed water to the RO membrane. Without applied pressure, reverse osmosis is not possible.
Permeate osmotic pressure is the second of the two positive pressures making up NDP. Since the permeate is very low in dissolved solids, the osmotic pressure of the permeate is very low. For this reason, it is often left out of the NDP calculation. Osmotic pressure of the feed water is usually the largest of the two negative components of the NDP. It is a function of the amount of dissolved solids in the feed water and may be approximated by the following equation:
Osmotic Pressure (psi)=Total Dissolved Solids (mg/l)/100
Actual permeate pressure is the second of the two negative components of NDP. Actual permeate pressure is the back pressure placed upon the permeate during RO operation. It is usually a result of back pressure placed upon the permeate by a control valve or hydrostatic pressure from an overhead permeate tank. In some cases, there may be no permeate pressure.
The NDP is calculated with the following equation:
NDP=Pa+PoPxe2x88x92Pofxe2x88x92Pp
Where:
Pa=Applied Pressure
PoP=Osmotic Pressure of Permeate
Pof=Osmotic Pressure of Feed Water
PP=Permeate Pressure
Since the osmotic pressure of the permeate is usually very low, it is often left out of the NDP equation resulting in:
NDP=Paxe2x88x92Pofxe2x88x92Pp
There are an infinite number of NDPs in the RO system from feed water inlet to reject outlet. This is due to the fact that the applied pressure decreases as the feed water progresses from the inlet to the outlet. This pressure decrease results from the pressure drop across the feedspacer as the water flows through the membrane elements.
Likewise, the osmotic pressure of the feed water increases as the water flows from the feed water inlet to the reject outlet. This is due to the increase in feed water total dissolved solids (TDS) as permeate passes through membrane. Since these pressures change from the feed water inlet to the reject outlet, it is necessary to take the average of the applied pressure and the feed water osmotic pressure across the RO unit. Using these average values in the NDP equation results in the average net drive pressure. It is this average NDP which is used in the calculation of normalized permeate flow.
Water temperature has an effect on the amount of water which is permeated through a given amount of membrane under a given net drive pressure. As water temperature drops, water becomes slightly more viscous and more difficult to force through the membrane. Likewise, as the temperature increases, water is more easily forced through the membrane. These changes in permeate flow due to temperature changes in the feed water do not indicate problems with the membrane. They do, however, need to be taken into consideration when calculating normalized permeate flow. This is done by using a temperature correction factor (TCF). These factors are determined experimentally by the membrane manufacturer and are used in the normalized permeate flow calculation to account for changes in permeate flow due to changes in temperature. Some typical temperature correction factors are listed below in Table 3. Each type of membrane will have a different set of temperature correction factors.
Normalized permeate flow may be calculated by means of the following equation:
NPF=(NDPs/NDPa)xc3x97TCFxc3x97FP
Where:
NDPs=Net Drive Pressure at standard conditions (start up conditions are often used as standard conditions)
NDPa=Net Drive Pressure at Actual Conditions
TCF=Temperature Correction Factor for Actual Temperature
FP=Actual Permeate Flow
The following is an example of an NPF calculation using the information listed below in Table 4. In this example, start up data is used as the standard.
The first step is calculating NPF at start up. The NDP must be calculated first.
NDPs=Paxe2x88x92Pofxe2x88x92PP 
NDPs=195 psixe2x88x9250 psixe2x88x9215 psi
NDPs=130 psi
Next, the NPF equation. *Since this is the NPF at start up, both NDPs in this equation are the same:
NPFs=(NDPs/NDPa)xc3x97TCFxc3x97FP
NPFs=(130 psi/130 psi*)xc3x971.172xc3x9725 gpm
NPFs=29 gpm
Next, the actual (today""s) NPF is calculated. First, the actual NDP:
NDPa=Paxe2x88x92Pofxe2x88x92PP 
NDPa=205 psixe2x88x9245 psixe2x88x9215 psi
NDPa=145 psi
The NPF equation:
NPFa=(NDPs/NDPa)xc3x97TCFxc3x97FP
NPFa=(130 psi/145 psi)xc3x970.857xc3x9725 gpm
NPFa=19 gpm
The results show that there is a vast difference between the two NPF values, 29 gpm versus 19 gpm. This indicates that the membrane condition has changed over the first few months of operation. If the RO operator had been using the actual permeate flow rate as an indicator of performance, this change in membrane condition would not have been noticed. However, by normalizing the permeate flow, the changes that occurred over the months in NDP and water temperature were accounted for. By comparing the two normalized permeate flows, the change in membrane condition can be clearly identified.
This example revealed a dramatic change in membrane condition that occurred over several months. From this example, it should be obvious that normalized permeate flow should be calculated more often than every few months. Had the NPF in this example been calculated more frequently, possibly once per day, a gradual downward trend in NPF would have been noticed. It is this gradual downward trend in NPF that indicates the onset of membrane fouling or scaling. If remedies are not taken, the rate of NPF decline becomes greater. If the NPF drops too far, irreparable membrane damage will likely be the result.
A reference point is needed in order to measure the decline in NPF. This reference point is the amount of permeate flow expected from the NDP and temperature to which the permeate flow is being normalized (usually start up or standard conditions). If modern thin film composite membranes are being used, the expected permeate flow does not change very significantly from that experienced within a few days after start up. Normalizing to these start up conditions and comparing NPF to the start up NPF is an acceptable way of monitoring most RO systems using thin film composite membrane. Cellulose acetate (CA) membrane poses a slightly different situation. CA membrane exhibits a normal flux decline over time due to membrane compaction. When normalizing permeate flow from CA membrane it may be necessary to take this normal flux decline into effect.
As the condition of the membrane declines, the NPF drops below the curve showing the expected permeate flow. When the NPF drops to approximately 15% below that expected, the membrane should be cleaned and NPF should increase to match the expected permeate flow.
Monitoring RO performance is not difficult but is time-consuming and tedious. A great number of RO failures can be attributed to poor monitoring. There are generally three reasons why an RO unit is not monitored properly. The failure to record raw data is probably the most common problem in RO monitoring, especially in the case of smaller RO systems. Manually recording raw data by writing it down on log sheets is a time-consuming process. Many small RO systems may only be manned a portion of the time thus allowing even less time for data recording. Many RO systems have inadequate or inoperable instrumentation. This may result in missing or inaccurate data points even when the data is recorded.
Failure to analyze raw data is another problem. Raw data does little good in determining the operating status of an RO unit without at least some data analysis. Unfortunately, data analysis is also a time-consuming process since calculations must be made. There are a number of computer programs which make it easier to examine and analyze RO data but in most cases the raw data still has to be entered into a computer. Many times the raw data does not get analyzed until membrane damage occurs. This will often identify the cause of the problem. However, had the data been analyzed in real time, it is likely that the problem could have been corrected before the damage occurred.
Failure to respond after data analysis may be most detrimental to RO operation. Failure to respond to the information provided by on-going data analysis can happen for a number of reasons. The person conducting the analysis may not be trained to identify the trends indicating a problem. It may also be a result of poor communication. This may be the case when data analysis is done in a central location and the results of the analysis have to be communicated back to field personnel.
In summary, the ability to monitor an RO unit is dependent upon the availability of raw operating data. If raw data is not recorded, it will not be normalized, trended, and used to monitor RO performance. Manual record-keeping can be a time-consuming and tedious process, especially if multiple RO units are involved. The use of computerized data acquisition equipment in RO applications can assure that raw data is recorded in an accurate and timely manner. Although the gathering and recording of raw data does not guarantee that the data will be analyzed, it is the first step toward proper RO monitoring.
A conventional prior art RO monitoring system consists of a group of individual instruments, gauges, and meters to display the primary parameters necessary for RO monitoring. In addition to these instruments, the RO unit is usually equipped with a xe2x80x9cwet panelxe2x80x9d. This is a separate panel holding pressure gauges and flow gauges, i.e., rotameters. The indicators in the wet panel must be physically connected by piping to the water being treated by the RO unit.
Typically the instruments making up a conventional RO monitoring system only monitor one parameter. This means that a relatively large number of instruments are needed and that each instrument must be programmed and calibrated separately. This can lead to some confusion if a number of instruments from different manufacturers are being used on the same system. Operating and calibration methods vary from manufacturer to manufacturer. On some of the prior art microprocessor-based instruments the menu structure can be quite involved since only a few keys are available to perform a multitude of functions.
FIG. 26 is a diagram of a typical prior art RO monitoring and control system using PLC 414 for logic control of the water treatment equipment via pumps, valves and switches at 522. (See also FIG. 12 discussed below.) Signals from instrumentation shown generally at 532 coming from conductivity 526, flow 528, and pressure, or other analog inputs, 524 must be hardwired as shown generally at 530 to PLC 414. The operator interface consists of panel-mounted indicator lights and switches 520.
In most applications, data provided by the prior art monitoring systems must be transcribed by hand from the display of the instrument to some type of log sheet. In rare occasions, analog outputs from the panel-mounted instruments may be routed to a data acquisition system or strip chart recorder. If the latter is used, data must still be manually transcribed at some point. Real-time response to instrument output is commonly available in the form of relay outputs for various discrete alarm set-points. The relay outputs are commonly used to illuminate indicator lights or signal a programmable logic controller (PLC) of an alarm condition. Since only the primary RO operating parameters are being monitored by the instruments, the alarms are based only on the condition of these primary parameters. Calculated parameters remain a mystery until the data is logged and proper calculations are performed.
Illustrative of the prior art of reverse osmosis systems are U.S. Pat. No. 5,647,973, to Desaulniers, entitled Reverse Osmosis Filtration System with Concentrate Recycling Controlled by Upstream Conductivity, U.S. Pat. No. 5,646,863, to Morton, entitled Method and Apparatus for Detecting and Classifying Contaminants in Water; U.S. Pat. No. 5,422,014, to Allen et al., entitled Automatic Chemical Monitor and Control System; U.S. Pat. No. 4,849,098, to Wilcock et al., entitled Continuous Water Quality Monitor; U.S. Pat. No. 4,587,518, to King, entitled Monitor and Control System for Water Purification Apparatus; and U.S. Pat. No. 4,498,982, to Skinner, entitled Reverse Osmosis Water Purification System. Illustrative of the prior art relating to pressure sensing manifolds are U.S. Pat. No. 5,967,167, to Johnson, entitled Remote Controlled Drinker System; U.S. Pat. No. 5,852,563, to Weber et al., entitled Intelligent Coolant Flow Control System; U.S. Pat. No. 5,808,909, to Rees, entitled Electronic Brake Control Valve Tester for Rail Cars and Trains; U.S. Pat. No. 5,566,717, to Robert, entitled Assembly for Controlling Fluid Passing Through a Manifold; U.S. Pat. No. 5,519,636, to Stoll et al., entitled Electronic Control Device for a Valve Range of Modular Design; U.S. Pat. No. 5,384,709, to Seder et al., entitled Miniature Fluorescent Lamp Processing Apparatus; U.S. Pat. No. 5,351,705, to Reinders et al., entitled Method and Apparatus for Controlling Fluid Pumps and Valves to Regulate Fluid Pressure and to Eliminated Fluid Flow Surges; U.S. Pat. No. 5,325,884, to Mirel et al., entitled Compressed Air Control System; U.S. Pat. No. 5,320,760, to Freund et al., entitled Method of Determining Filter Pluggage by Measuring Pressures; and U.S. Pat. No. Re. 29,383, to Gallatin et al., entitled Digital Fluid Flow Rate Measurement for Control System. 
The present invention is of a fluid monitoring and control apparatus and method comprising: providing a programmable and reprogrammable control unit comprising a display, user inputs, and input/output connectors; placing a programmable logic controller in direct communication with the control unit, which programmable logic controller is programmable and reprogrammable through the control unit; and placing a plurality of fluid parameter sensors in direct communication with the control unit. In the preferred embodiment, the control unit comprises a serial port for direct communication with the programmable logic controller and a network connection port for direct communication with the plurality of fluid parameter sensors. The programmable logic controller need have no inputs other than from the control unit. An integral housing is preferred to which the control unit and the plurality of sensors are attached and through which flows a fluid stream whose parameters are being sensed by the sensors. A pressure sensing manifold is employed cycling through a plurality of solenoid valves but requiring only a single input/output connection to the control unit.
The present invention is also of a fluid control apparatus and method comprising providing a membrane and estimating salt rejection by the membrane. In the preferred embodiment excessive changes in the salt rejection are detected. The estimating comprises detecting a concentration of dissolved solids in a permeate (CP), in feed water (CF), and in reject flow (CR), preferably by calculating CP/((CF+CR)/2). The control apparatus and method can also calculate recovery, differential pressure (DP), and normalized permeate flow (NPF).
A primary object of the present invention is to provide the ability to directly receive analytical parameters.
Another object of the present invention is to monitor and control a variety of fluid treatment parameters with one integrated programmable apparatus.
Yet another object of the present invention is to monitor and control fluid treatment parameters from a central location mounted on a single control panel.
Still another object of the present invention is to provide an integrated apparatus for monitoring and controlling fluid treatment parameters that is easily programmed and simple to operate.
A primary advantage of the present invention is that individual meters and gauges are not necessary to monitor and control fluid treatment parameters.